Enable the vnodesetup hackandwait parallelization hack for Docker.

clientside/tmcc/common/vnodesetup

@@ -955,7 +955,7 @@ sub hackwaitandexit($)
     elsif ($fakevnode) {
 	$goofy = CONFDIR() . "/evproxy.pid";
     }
-    elsif ($dojail && (-e "/vz" || -e "/etc/xen")) {
+    elsif ($dojail && (-e "/vz" || -e "/etc/xen" || -e "/etc/emulab/docker")) {
 	$goofy = CONFDIR() . "/running";
     }
     else {

clientside/tmcc/linux/docker/libvnode_docker.pm

@@ -128,6 +128,15 @@ my $debug  = 0;
 my $lockdebug = 0;
 my $sleepdebug = 0;
 
+#
+# Set to enable vnodesetup to exit before vnode is completely up
+# (see vnodesetup::hackwaitandexit). Allows more parallelism during
+# boot-time vnode setup. Note that concurrency may still be constrained
+# by $MAXCONCURRENT (defined below) which limits how many new VMs can
+# be created at once.
+#
+my $vsrelease = "immediate";	# or "early" or "none"
+
 #
 # Should we use LVM for extra storage space?  This should remain set.
 #
@@ -1776,6 +1785,17 @@ sub rootPreConfigNetwork($$$$)
 	if ($lockdebug);
     TBScriptUnlock();
 
+    #
+    # Let vnodesetup exit early, so that bootvnodes delays minimally per
+    # vnode.  I guess we figure if we can get through this call, we've
+    # made it through the obvious failures in the overall preparatory
+    # code in mkvnode.pl.
+    #
+    if ($vsrelease eq "immediate") {
+	TBDebugTimeStamp("rootPreConfigNetwork: touching $VMS/$vnode_id/running");
+	mysystem2("touch $VMS/$vnode_id/running");
+    }
+
     return 0;
 
   bad: